Perioperative Pain Management

Perioperative Pain Fundamentals - Setting the Stage

• Perioperative pain: Acute pain occurring before, during, and after surgery.
• Effective management is crucial:
  • Reduces complications (e.g., DVT, atelectasis, ileus)
  • Improves patient satisfaction & outcomes
  • Facilitates early mobilization & faster recovery
  • Prevents Chronic Post-Surgical Pain (CPSP)
• Key Pain Types:
  • Nociceptive: Activation of nociceptors (somatic, visceral)
  • Neuropathic: Lesion or disease of somatosensory nervous system
  • Nociplastic: Altered nociception despite no clear evidence of tissue damage or neuropathy (e.g., fibromyalgia)
• Core Principle: Multimodal Analgesia (MMA) - using ≥2 analgesic agents/techniques with different mechanisms.

⭐ Inadequate acute postoperative pain control is a primary risk factor for developing Chronic Post-Surgical Pain (CPSP), which can affect 10-50% of patients after common surgeries, significantly impacting quality of life.

Pre-Op & Intra-Op Game Plan - Pain Blockade Tactics

• Pre-Op Game Plan:

  • Assess: Pain Hx, anxiety, comorbidities, current medications.
  • Counsel: Discuss pain management plan, set realistic expectations.
  • Pre-emptive Analgesia (PO): 📌 GAP Mnemonic
    • Gabapentinoid (e.g., Pregabalin 75-150mg) if high neuropathic risk.
    • Acetaminophen (Paracetamol 1g).
    • PNSAID (e.g., Etoricoxib 60-120mg).

• Intra-Op Blockade Tactics:

  • Core Principle: Multimodal Analgesia (MMA).
  • Regional Anesthesia (RA) - Prioritize when feasible:
    • Neuraxial: Epidural (catheter for post-op analgesia), Spinal.
    • Peripheral Nerve Blocks (PNBs): Ultrasound-guided (USG) for accuracy (e.g., Brachial plexus, Femoral, TAP block).
  • Systemic Adjuncts (Opioid-Sparing Focus):
    • IV Paracetamol 1g.
    • IV NSAID (e.g., Ketorolac 30mg).
    • Low-dose Ketamine (e.g., 0.25-0.5mg/kg bolus, then 2-5mcg/kg/min infusion).
    • IV Lidocaine infusion (e.g., 1.5mg/kg bolus, then 1-2mg/kg/hr).
    • Dexamethasone (4-8mg IV) - anti-inflammatory, anti-emetic effects.

⭐ Employing regional anesthesia as part of MMA significantly ↓ opioid needs, enhancing recovery & ↓ adverse effects.

Post-Op Pain Control - The Recovery Blueprint

• Goal: Optimal analgesia, facilitate early mobilization, ↓post-op complications.
• Assessment: Regular pain scores (VAS, NRS); reassess post-intervention. Document findings.
• Multimodal Analgesia (MMA): Core strategy. Synergistic effect, ↓opioid needs & side effects.
  • Paracetamol: IV/Oral. Max 4g/day. Foundational.
  • NSAIDs/COXIBs: e.g., Ketorolac. ⚠️ GI/Renal/CV risks.
  • Opioids: IV PCA (Morphine), Oral (Tramadol). Monitor sedation, N/V. Naloxone for reversal.
  • Regional: Epidurals, Nerve blocks (e.g., TAP). Excellent for major surgery.
  • Adjuvants: Gabapentinoids, low-dose Ketamine. Target neuropathic elements.
• ERAS Protocols: Emphasize opioid-sparing, early nutrition & ambulation.

⭐ IV Paracetamol 1g Q6H is a cornerstone of opioid-sparing multimodal analgesia, significantly reducing total opioid consumption.

Special Scenarios & Sidekicks - Managing Curveballs

• Opioid-Tolerant: ↑ baseline needs (25-100% more). Multimodal vital (ketamine, regional).
• Chronic Pain Pts: Continue baseline meds. Manage expectations. Multimodal for acute pain.
• Obstructive Sleep Apnea (OSA): High OIRD risk. 📌 STOP-BANG (≥3 high risk). Prefer regional, non-opioids. Cautious opioids, CPAP.
• Elderly: ↓ clearance, ↑ sensitivity. "Start low, go slow." Reduce NSAID/opioid doses (e.g., by 50%).
• Renal Impairment (e.g., GFR <30 mL/min): Avoid morphine, NSAIDs. Fentanyl, paracetamol safer.
• Hepatic Impairment: Paracetamol max 2g/day. Cautious opioid titration (e.g., fentanyl, hydromorphone).
• Acute Pain Service (APS): Consult for complex pain, advanced techniques (e.g., PCA, epidurals).

⭐ For patients on chronic buprenorphine, continue it perioperatively and add short-acting opioids as needed for acute pain; do not abruptly stop buprenorphine due to withdrawal risk and difficult pain control.

High‑Yield Points - ⚡ Biggest Takeaways

• Multimodal analgesia is standard care, combining diverse drug classes for optimal effect.
• Pre-emptive analgesia, administered before incision, aims to minimize central sensitization.
• Regional techniques (epidurals, nerve blocks) offer excellent pain relief and reduce systemic opioid needs.
• NSAIDs and Paracetamol are key opioid-sparing drugs; always check NSAID contraindications.
• Opioids provide potent analgesia; monitor closely for respiratory depression and other side effects.
• Consider Gabapentinoids as adjuvants for neuropathic pain and reducing opioid use.